| Continuity between series in Doctor Who was never a strong point. Why lose a perfectly good nasty enemy just because you have destroyed them?
Besides The Doctor shuttles backwards and forwards through time and relativity, so perhaps timelines are not so critical?
I suppose if you want to be really pernickity you could start with Tom Baker and the Genesis of the Daleks, then comes the dealings with the Tharl with William Hartnell back in the 60's.
Though this does not really work, it broadly gives two creation points. The original suggested that the Tharl created the Daleks themselves |